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(04-17-2022, 08:49 PM)StuartC Wrote: The machine tells me that it did very little to help, it reported spontaneous trigger of 6% and spontaneous cycle of 91%. The charts show the same thing. Most of the time the machine controlled: pressure at or near IPAP max, respiratory rate close to 12, tidal volume around 580 and minute vent quite consistent.
This seems contradictory to me. If "the machine controlled" (and this is supported by the RR which is solid as a rock) then did not the machine do a whole lot to help?
IMO those FLs do not look like FLs, they look like machine breaths w/o any spontaneous input (which should be square waves) terminated by I:time max.
(04-16-2022, 06:52 AM)StuartC Wrote: Less sensitive / slower to trigger a machine initiated breath and more opportunity for a spontaneous breath to be initiated.
I would not put it that way, nor would I consider there to be any "more opportunity for a spontaneous breath to be initiated". If you want more opportunity for a spontaneous breath to be initiated, change the back up rate. Don't add more work to generate breaths.
Machine: Resmed Lumis VPAP 150 ST Mask Type: Full face mask Mask Make & Model: Evora Full Humidifier: Resmed Lumis VPAP 150 ST CPAP Pressure: EPAP 5, PS 5 - 7 in iVAPS mode CPAP Software: OSCAR
Other Software
Other Comments: O2 desaturation during REM when untreated or on CPAP. High CO2 on CPAP even with normal O2
Sorry, that was me being a bit short-handed again in terms of what "it" refers to. In this case, I am referring back to the previous posts and the change made for last night. Let me explain better.
One of the settings that I have been struggling with is the backup rate. The sleep study recommends a setting of 10 because 12 was too close to my respiratory rate. But the iVAPS mode does not use a simple backup such as that, it uses an "intelligent backup rate", which has two values. The upper value is entered as a setting called "Target Patient Rate" and the clinical manual says this should be my spontaneous respiratory rate, so 12 or 13. The lower value is calculated to be two thirds of the Target Patient Rate.
As I understand it, the machine is supposed to allow me to breathe at and around my target patient rate without interference and only trigger inhalation "during sustained apnea". But I have been finding that it triggers 85 to 90 % of the time, even without apneas indicated. I have never had or needed the machine to trigger inhalation while using fixed CPAP or for the short time that I ran with S mode Bilevel, so I was trying to work out what I could do for the machine to allow me to trigger spontaneously. I did have some success with that by entering a target patient rate of 10, but seemed to allow my rate to drop even lower than that (minimum would be 6.7) and I did not achieve the tidal volumes that the sleep study suggests. Instead I set the target patient rate back to 12 and changed the trigger sensitivity, from medium to very low. That change of trigger sensitivity was the "it" that did very little to help to allow me to initiate inhalation spontaneously.
Yes, you are correct, the machine did do a lot to regulate my respiratory rate, which helped to regulate my tidal volume. But is that appropriate? Or is it better that I breathe spontaneously?
Thank you for your comment about the wave shape. I have zoomed right in and confirmed that the inhalation time is 2.5 seconds long, which is the setting that I have for Ti max. So, it looks as though you are correct and I have just learned something, but it shows that I have a lot more to learn and raises more questions. The most important is still "what should I do about it?". That square shape clearly occurs during the period from 3:56 to 4:30 and sometimes, but not so much, at other times during the night. Is it still appropriate to do as I was thinking - enable AutoEPAP to allow that to increase?
04-18-2022, 06:57 AM (This post was last modified: 04-18-2022, 07:09 AM by Rubicon.)
RE: Therapy using Lumis 150 ST
IMO you need to figure out what you got. Going back to your PSG and screenshots while on CPAP you go right down the tubes when REM happens. Again, as we briefly discussed, REM breathing is largely controlled by the diaphragm, so that significant hypoventilation during what certainly appears REM strongly suggests diaphragmatic paralysis. Since it appears like central hypoventilation EPAP fiddling would not be the way to go.
You would like all breathing to be spontaneous otherwise you could be driving your pCO2 into God knows where. That said, given the history, you should probably see machine breaths during REM periods cause that's where the central hypoventilation occurs. That said2, machine breaths all night means settings are too aggressive. That said3 based on O2 sat and breathing pattern the settings don't look all that bad. That said4 what you're really trying to do is manipulate pCO2 (normalize during REM, don't overventilate in NREM) so you really need some capnography to get this correct.
Also use this template on a shot of 4/15 cause I think it looked good but it was all machine breaths (although I'm like meh cause the parameters really aren't off the wall).
Machine: Resmed Lumis VPAP 150 ST Mask Type: Full face mask Mask Make & Model: Evora Full Humidifier: Resmed Lumis VPAP 150 ST CPAP Pressure: EPAP 5, PS 5 - 7 in iVAPS mode CPAP Software: OSCAR
Other Software
Other Comments: O2 desaturation during REM when untreated or on CPAP. High CO2 on CPAP even with normal O2
In other words, hurry up and find a new respiratory specialist? The importance of that is becoming quite apparent and I have an appointment tomorrow that I hope will help that along.
Can I do anything in the meantime? For instance, I have tried setting the target patient rate to 10, 12, 13 and 14, should I try 11 just to complete the range and possibly increase my proportion of spontaneous breaths to somewhere between 5 and 85%? At the very least, maybe I would learn something.
Another idea, I don't know whether this is conservative or slightly more "out there", should I simply switch to ST mode until I see the specialist? Settings of EPAP = 5, IPAP = set to achieve a tidal volume that is roughly in the desired range (probably between 12 and 14 cmH2O) and standard backup rate set to 10? I used settings like this when I trialed a Prisma 30ST, from which I could not import data into OSCAR, and the oximetry results were better than CPAP, even if nothing else.
I really do appreciate your help. Just what you have said about probable diaphragm involvement is more progress in a much shorter time than I have had from anyone else.
Machine: Resmed Lumis VPAP 150 ST Mask Type: Full face mask Mask Make & Model: Evora Full Humidifier: Resmed Lumis VPAP 150 ST CPAP Pressure: EPAP 5, PS 5 - 7 in iVAPS mode CPAP Software: OSCAR
Other Software
Other Comments: O2 desaturation during REM when untreated or on CPAP. High CO2 on CPAP even with normal O2
I have given you the three days from the 15th to the 17th. The 16th was the day that I set Target Patient Rate to 10, whereas it was 12 for the 15th and 17th.
Machine: Resmed Lumis VPAP 150 ST Mask Type: Full face mask Mask Make & Model: Evora Full Humidifier: Resmed Lumis VPAP 150 ST CPAP Pressure: EPAP 5, PS 5 - 7 in iVAPS mode CPAP Software: OSCAR
Other Software
Other Comments: O2 desaturation during REM when untreated or on CPAP. High CO2 on CPAP even with normal O2
Oh, I forgot to answer your question about where my REM periods are.
No, using the Lumis, it is not (as) clear where my REM periods are because my oxygen levels do not drop as they did on CPAP. But I agree that the period on the 17th with reduced flow is in the right place for REM. If you look at the timing of the oxygen desaturations from the CPAP chart, I have dozens more that have really similar timing.
I have attached a couple of pages that I compiled and took to the specialist to show him that this was a regular occurrence.
04-18-2022, 08:54 AM (This post was last modified: 04-18-2022, 08:54 AM by Rubicon.)
RE: Therapy using Lumis 150 ST
So IMO you have 3 goals:
1. Quality sleep.
2. Adequate oxygenation.
3. Normal pCO2.
As an aside, your REM periods are going to be pretty much in the same spot every night. The CPAP screenshot will be a good template.
IMO your sleep and oxygenation look good, and with a Minute Ventilation of 7.00 to 8.00 L your pCO2 should be fine.
Overall, I believe what's happening is that while you breath spontaneously, only EPAP is used and you're happy. Once you start iVAPSing tho you immediately overventilate, your drive to breathe is shot for the rest of the night and you end up with machine breaths. I think the first half of Saturday is how you eventually want to look, with iVAPS attacking what I believe to be the first 2 REM periods while you spontaneously breath during NREM.